Electric circuit breaker and the like



B. H. LEESON ELECTRIC CIRCUIT BREAKER AND THE LIKE Filed March 13, 1924 3 Sheets-Sheet l Jan. 13. 1925. 1,523,266

B. H. LEESON ELECTRIC CIRCUIT BREAKER AND THE LIKE Filed March 15, 1924 3 Sheets-Sheet 2 IIYIEYIOR Jam; 13.21925. 1 1,523,266

" s. H. LEESON ELECTRIC CIRCUIT BREAKER AND THE LIKE I Filed March 13, 1924 3 Sheets$heet 5 Inmyroiff mv w Patented Jan. 13, 1925,

UNITED STATES PATENT OFFICE.

BRUCE HAMER LEESON, OF TYNEMOUTI-I, ENGLAND. ASSIGNOR TO A. REYROLLE & COMPANY LIMITED, OF HEBBURN-ON-TYNE, ENGLAND. A COMPANY REGISTER/D UNDER THE LAWS OF GREAT BRITAIN.

ELECTRIC CIRCUIT BREAKER AND THE LIKE.

Application filed. March 13, 1924,

To (/ZZ whom it may concern.

Be it known that I. BRUCE Hanna LEE- sox, a subject of the King of England, and residing at Tynemouth, county of Northum- I berland. England, have invented certain new and useful Improvements in Electric Circuit Breakers and the like, of which the following is a specification.

This invention relates to electric circuitbreakers and the like and has particular reference to circuit-breakers intended to open very quickly a circuit under heavy load.

hen dealing with large power circuits these breakers have to be made of comparatively heavy parts subjected to strong forces and difiiculties sometimes arise in resetting or reclosing them especially when such operations are performed under load. Sometimes this difficulty is avoided by employing another separate contactor or circuit-breaker which is closed after the main high speed breaker has been reset, i. e. after its contacts have been brought together.

The primary object of the present invention is the construction of a high speed contact breaker in which, without the employment of such separate contactor or circuit-breaker, the resetting of the main contact and mechanism, whose function it is to break or open the circuit quickly, can be effected quite freely.

This is accomplished. according to this invention by so constructing the other main contact, i. e. that one which is not neces sarily moved at high speed to open the circuit. that it is capable of being moved from its closed position and then returned after the high speed contact has been reset. Thus the primary function of one main contact is to break the circuit and that of the other to make it.

The movement of the second or closing main contact may be by means of an inde pendent electromagnet which may operate upon the contact directly or through some form of tripping mechanism, or again such movement may be controlled by the movement of the other or high speed main con- 90 tact.

Whatever the construction employed it is desirable that the opening movement of the high speed contact and its resetting Serial No. 699,054.

movement shall be free any time.

The invention is particularly suitable for application to a high speed contact breaker of the kind described in the specification of application for Letters Patent of United States of America Serial No. 698,503, filed on Mar. 11, 1924:, where the movement of the high speed or breaking main contact is caused by an armature which is pivoted so as to move up and down in a gap between the poles of two electromagnets, one electromagnet being series wound and tending to move the armature so as to break the circuit whilst the other is shunt wound and acts normally to hold the armature in and unhampered at such a posit-ion that the contacts are closed.

This shunt or potential electromagnet may act to reset the high speed main contact and thus when the present invention is applied to a circuit-breaker of this construction the action of the shunt wound or potential electromagnet in returning the armature and resetting the high speed main contact. can be made absolutely free, for when that contact is returned to its posi tion the main circuit is still broken until the other main contact is moved into its closed position.

But when. in a contact breaker of this kind, the resetting operation is performed by the potential electromagnet it is usually necessary to provide an extra winding for that purpose as the armature is away from the poles and the flux tends to leak across through the air from pole to pole. Therefore it is preferred. according to the present invention to perform the resetting operation by means of the electromagnet or other mechanism which opens the second orslow speed main contact. Thus the functions of the potential electromagnet are to hold and release the armature which is returned or reset by the separate electromagnet.

When this construction is adopted the leakage above mentioned instead of being a disadvantage is beneficial and conveniently the poles of the potential electromagnet may be fairly close together so that great leakage takes place immediately the armature starts to move away from the poles. It will be appreciated that this increases the rapidity of the breaking action.

In one construction of. high speed circuitbreaker according to this invention, whilst the main features are as described in the above mentioned specification, the second or closing main contact is mounted on a shaft rocked by a crank arm connected by a rod to the armature of a closing electroniagnet or solenoid. This connecting rod is joined by a pivoted link say to the same spindle as that u on which the main armature is pivoted. This link is pulled down when the closing or resetting electromagnet 1S energized and it then presses onthe armature and pulls it down on to the poles of the potential magnet, thus resetting it and also returning the high speed main contact to its closed position.

Conveniently the resettitng or closing electromagnet may work against the action of a spring which returns the closing main contact when the resetting electromagnet is (ls-energized but obviously other arrangements may be adopted. In any case the mechanism. is so arranged that as soon the resettitng action is completed the main armature is left quite-free of all restraint due tothe resettitng mechanism.

In all high speed circuit-breakers of the general type to which this invention is applicable, it is desirable to provide arcing contacts so the circuit is broken shall not take place on the main contact. or current carrying surfaces. Inthespecification of British Letters Patent No. 167846 a particular arrangement of suchsparking contacts is described and a circuit-breaker according to the present inventioiris preferably provided with contacts acting in a similar way. In the specification referred to one of the main contacts is provided with a shaped sparking contact moved in relation to. the main contact by meansof a spring. Such a construction has many advantages in practice and when as is prefered it is adopted in carryi-ng out the present invention the jointed or heavy main contact COHStllZUtGSWVllRt has been termed'the closing contact and thus its weight is'not a disadvantage as it does not. necessarily move at a high speed. The other high speed main contact may be of lighter constructionand as described in British specification No. 167846, would not be jointed.

In the accompanying drawings,

. Figures 1, 2' and 3 are elevations showing diagrammatically the essential parts of a circuit-breaker according to this invention in difierent: positions, and

Figure 4 is a view taken in a direction at right angles to Figures 1, 2 and S and showingpart of the magnetic circuit. 7

So far as the general arrangement of the magnetic circuit of the circuit-breaker is concerned the form illustrated corresponds that the are which occurs when to that described in the specification of the prior patent application of the United States of America Serial No. 698,503 previously mentioned that is to say there are two U-shaped cores, one A provided-with a series winding A andthe other B'having a shunt or potential winding B" and in the gap between the poles of these two cores an armature C can move such armature being pivoted as at C. The function of the series wound magnet A is to pull up the armature G on the passage ofan overload or short circuit current through the series winding and the function of the shunt wound magnet B- is primarily to hold the armature G down until the overload or short circuit.

conditions cause it to. be released and to be raised by the series wound mag-netz Also as in the construction previously referred to the armature is connected by a rod D to a crank arm E which rocks a shaft E upon which one of the main contacts F is mounted. This contact. I? and the other main contact G with its auxiliary or sparking contact G are situated in a gap in the series magnet A; sothat the circuit is broken in a strong magnetic field.

As will be seen by reference to Figures 1. 2 and 3 the main contact F which will be referred to as the high speed contact is light as compared with the other contact G G and has no parts which move relatively to each other. Inthe other contact G G which may be termed'the closing contact the auxiliary or sparking contact G is pivoted as at G and can move relatively to the main contact G through the action of a spring G The arrangement and function of this auxiliary or sparking contact G need not be particularly described as it corresponds, generally to that referred to in the specification of the prior British Patent No. 1678et6. v The closing contact G G is mounted upon ash-aft H which can be rocked by means of a crank arm H connected by a rod H to the core J of asolenoid or electroinagnet J, aspring K being provided which acts in opposition to the pull exerted by the solenoid or electromagnet J. V

Pivoted to the shaft C, about which the armature C is also pivoted, is a resetting arm L connected as by a slot and pin at L to the rod I and provided with a protuberanceL clear of the armature C in all positions except when the rod L is moving downwards to reset the armature C In Figure l the armature C its lower position in proximity to the poles of the holding electromagnet B and both the main contacts are closed. Ifnow the current in the series winding A increases due is shown in say to an overload or short circuit on ashunt the same time the force exerted by the shunt or potential coil B will be diminished owing to the drop of voltage and the armature C will rise extremely quickly to the position shown in Figure 2. In making this motion the armature moves independently of its pivot C and is quite tree and unhampered by the resetting arm L and its operating mechanism. As shown in Figure 2 this upward movement of the armature moves the high speed or opening contact F and breaks the main circuit.

To reset the circuit-breaker the electro magnet or solenoid J is energized and this pulls down the resetting arm L, returns the armature C into its original position in proximity to the poles of the shunt wound magnet B and also rocks the shaft H moving the closing contact Gr G away from the main contact F as shown in Figure 3. The downward or resetting movement of the armature C brings the main contact F back into the position which it is shown as occupying in Figure 1 and as soon as the electro magnet or solenoid J is de-energized the spring K rocks the shaft H back into its original position and the main circuit is completed by the main contact G Gr returning to its original position. During this movement the resetting arm L is lifted and thus the armature C is left so that it is quite free to move rapidly upwards again should the conditions of the circuit require it to do so.

Figure 4 is intended to show diagram matically a preferred construction of the series magnet cores A and the shunt magnet cores B. It will be seen that the poles B of the core B extend inwards so that they are comparatively close to each other. The effect of this is to increase the speed of breaking by means of the magnetic leakage which will take place across the gap bet-ween the poles B as soon as the armature C starts to move away from those poles.

It is to be understood that the details of construction of the improved circuit-breaker may be varied and that the resetting movement of the armature need not necessarily be brought about by an electromagnet or solenoid. For instance the arm L may b arranged to be hand-operated.

hat I claim as my invention and dc sire to secure by Letters Patent is 1. In an electric circuit-breaker the combination of a main contact, means for moving said contact at high speed to open the circuit and to return said contact to its closed position, a second main contact, and means for moving said second contact and to return it to close the circuit after the first main contact has been returned to its closed position.

2. In an electric circuit-breaker the combination of a main contact, electromagnetic means for moving said contact at high speed to open the circuit, a second main contact, and means for returning the first main contact to its closed or reset position such means also acting to move the second main contact away from its initial or closed position.

In an electric circuit-breaker the combination of a main'contact, electromagnetic means for moving said contact at high speed to open the circuit, a second main contact, means for returning the first main contact to its closed or reset position such means also acting to move the second main contact away from its initial or closed position, and means for returning said second contact to its initial or closed position to close the circuit after the first main contact has been returned.

l. In an electric circuit-breaker the combination of a main contact, electromagnetic means tor moving said contact at high speed to open the circuit, a second main contact, electromagnetic means for returning the first main contact to its closed or reset position such means also acting to move the second main contact away from its initial or closed position, and means for returning said second contact to its initial or closed position to close the circuit after the first main contact has been returned.

In an electric circuit-breaker the combination of a series wound electromagnet, a shunt wound electromagnet, an armature mounted to move in a gap between the poles of said electromagnets, a main contact, an operative connection between the armature and such main contact, a second main contact, a resetting electromagnet, an operative connection between said resetting electromagnet and the armature. an operative connection between the resetting electromagnet and the second main contact, and a spring for returning the second main contact to its closed position after the armature has been reset said spring also acting to return the operative connection between the armature and the resetting elcctromagnet to leave the armature tree and unhampcred for the next opening movement of the first main contact.

6. In an electric circuit-breaker the combination of a series wound electromagnet, a shunt wound electromagnet, an armature mounted to move in a gap between the poles of said electromagnets, a main contact in a magnetic field in a gap in the magnetic circuit of the series wound electromagnet, an operative connection between the armature and such main contact, a second main contact, a resetting electromagnet, an operative connection between said resetting electromagnet and the armature, an operative connection between the resetting electromagnet and the second main contact, and a spring for returning the second main contact to itsclosed position after the armature has been reset said spring also acting to return the operative connection between the armature and the resetting electromagnet to leave the armature tree and unhanipered for the next opening movement of the first main contact.

7. In an electric circuit-breaker the combination of a series wound electromagnet, ashunt wound electromagnet, an armature mounted to move in a gap between the poles of. said electromagnets, a main contact in a magnetic field in a gap in the magnetic circuit of the series wound electromagnet, an operative connection between the armature. and such main contact, a second main contact, an auxiliary or arcing contact pivoted to the second main contact, a spring actuating said arcing contact, a' resetting electromagnet, an operative connection between said resetting electromagnet and the armature, an operative connection between the resetting electromagnet and the second main contact, and a spring for returning the second main contact to its closed position after the armature has been reset said spring also. acting to return the operative connec- S. In an electric circuit-breaker the combination of a series wound electromagnet, a shunt wound electromagnet having a short leakage path between its poles, an arma ture mounted to move in a gap between the poles of said electromagnets, a main contact, an operative connection between the armature and such main contact, a second main contact, a resetting electromagnet, an operative connection between said resetting clectromagnet and the arn'iature, an operative connection between the resetting elec: tromagnet and the second main contact, and a spring for returning the second main contact to its closed position after the armature has been reset sai d'spring also acting to return the operative connection between the armature and the resetting electromagnet to leave the armature tree and unhampered for the next opening movement of the first main contact. y

In testimony whereof I have signed my name to thisspecification.

BRUCE HAMER LEESON. 

